Friday, December 05, 2008

Low-carb Diets Alter Glucose Formation By The Liver

In contrast to previous reports, the present study showed similar hepatic glucose production among the dietary groups. The low-carbohydrate group was able to maintain hepatic glucose production at the levels observed for the weight-stable and low-calorie groups by increasing glucose formation using lactate or amino acids to match the reduction in glucose formation from glycerol.

"This observation is reminiscent of 'hepatic autoregulation' by which endogenous glucose production remains unchanged in the setting of altered gluconeogenesis or glycogenolysis because the two pathways tend to compensate for each other," the authors report.

They noted it was interesting that the increased glucose formation using lactate or amino acids in the low-carbohydrate group was not associated with increased TCA cycle flux (i.e. energy production.) However, they did not measure absolute rates of fatty acid delivery to the liver or ketone body production, limiting their ability to further interpret that finding.

"We have shown that the sources from which endogenous glucose is produced are dependent upon dietary macronutrient composition," the authors write. They suggest that the shift in glucose metabolism associated with a low carbohydrate diet could be beneficial in individuals with non-alcoholic fatty liver disease (NAFLD) due to improved disposal of hepatic fat.

In conclusion, these findings may partly explain the correlation between carbohydrate intake and severity of liver disease in individuals with NAFLD.